i have an '86 engine in my crx, with an accord or prelude carb that I recently devaced. I got it cheap and it shows, with some minor work id gotten it running somewhat correct, and the devac fixed a lot, but its still had its little problems. I changed the leaky water pump today, and got everything lined back up and the timing belt back on, and pulled a thick wad of steel wool out of the exhaust pipe, and its running better, but still doesn't always want to start, and it backfires out of the exhaust randomly and fairly frequently, i tried adjusting the ignition timing, and it did help some, but it still backfires. any ideas? thanks.

 

Sounds like it's running lean. That would make sense if you are using a carb from a bigger motor (Accords are typically 1.8 to 2 liters.) I don't know if you can rejet the carb or not, but that might be what you need, or at least adjust the mixture. Does the backfiring typically happen after hard acceleration, or just putzing around nice and easy? Well it may not matter if the carb can't be rejetted. You'll need to take the top hat off and see. I'm actually surprised that it even had the same flange pattern as the CRX.

 

I think you should recheck your cam timing and then set your ignition timing with a timing light.

 

Your coil might be acting up

 

it was suggested that the valve timeing might be off by a tooth, so im going to try that first. some one used an adapter plate under the carb, and theyre similiar size to begin with, and it didnt pop before i did the water pump. I havent had it up to any speed, just around the yard, but it pops when its just idleing.

 

Another reason it might run lean, I just thought of, is if the carb base is leaking, or if you have a vacuum leak somewhere. Get a can of butane for for those butane soldering irons. You can point it around your engine bay and you will hear where your car sucks the butane in and pinpoint the possible leak.

EDIT: Oh I see, you didn't just now put the carb on. I misread your post, you did the water pump and now have the problem. Timing would make sense.

 

I tested the vacuum yesterday, and it was a little odd, it wouldn't be suprising if it had a vac leak either.

 

Well, you will definitely need to eliminate that. It will never work properly with a leak. It will always run weird and just cause you a ton of frustration.

 

Your cam timing is off.

 

ya, its deffenitely been a work in progress, I've sprayed carb cleaner on the outside of it and around the ports to try and find a leak, but havent had much luck, but will deffenitely look harder now. It's been hard to find time with school and work, but im hoping to fix the timing this weekend.